<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <div id="app">
    <h2>{{counter}}</h2>
    <!-- <h2 v-bind:title></h2> -->
    <!-- <h2 :title></h2> -->
    <!-- <button v-on:click="counter++">+</button>
<button v-on:click="counter--">-</button> -->
    <!-- <button v-on:click="increment">+</button>
    <button v-on:click="decrement">-</button> -->
    <!-- methods中 情况一：如果该方法本身中一个参数,那么会默认将原生事件event参数传递进去 -->
    <!-- 情况二:如果需要同时传入某个参数,同时需要event时,可以通过&event传入事件 -->
    <button @click="increment">+</button>
    <button @click="decrement">-</button>

  </div>
  <script src="../js/vue.js"></script>
  <script>
    const app = new Vue({
      el: '#app',
      data: {
        counter: 0
      },
      methods: {
        increment() {
          this.counter++
        },
        decrement() {
          this.counter--
        }
      }
    })
  </script>
</body>

</html>